{"id":"CVE-2026-22698","aliases":["GHSA-w3g8-fp6j-wvqw"],"url":"https://o3.security/vulnerability/CVE-2026-22698","summary":"RustCrypto SM2-PKE has 32-bit Biased Nonce Vulnerability","details":"RustCrypto: Elliptic Curves is general purpose Elliptic Curve Cryptography (ECC) support, including types and traits for representing various elliptic curve forms, scalars, points, and public/secret keys composed thereof. In versions 0.14.0-pre.0 and 0.14.0-rc.0, a  critical vulnerability exists in the SM2 Public Key Encryption (PKE) implementation where the ephemeral nonce k is generated with severely reduced entropy. A unit mismatch error causes the nonce generation function to request only 32 bits of randomness instead of the expected 256 bits. This reduces the security of the encryption from a 128-bit level to a trivial 16-bit level, allowing a practical attack to recover the nonce k and decrypt any ciphertext given only the public key and ciphertext. This issue has been patched via commit e4f7778.","published":"2026-01-10T05:17:19.993Z","modified":"2026-08-07T11:50:30.486806662Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"crates.io","name":"sm2","fixedVersion":null}],"fix":{"url":"https://github.com/RustCrypto/elliptic-curves/commit/4781762f23ff22ab34763410f648128055c93731","label":"RustCrypto/elliptic-curves@4781762"},"references":[{"type":"WEB","url":"https://crates.io/crates/sm2/0.14.0-pre.0"},{"type":"WEB","url":"https://crates.io/crates/sm2/0.14.0-rc.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/22xxx/CVE-2026-22698.json"},{"type":"ADVISORY","url":"https://github.com/RustCrypto/elliptic-curves/security/advisories/GHSA-w3g8-fp6j-wvqw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-22698"},{"type":"FIX","url":"https://github.com/RustCrypto/elliptic-curves/commit/4781762f23ff22ab34763410f648128055c93731"},{"type":"FIX","url":"https://github.com/RustCrypto/elliptic-curves/commit/e4f77788130d065d760e57fb109370827110a525"},{"type":"FIX","url":"https://github.com/RustCrypto/elliptic-curves/pull/1600"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:50:30.486806662Z"}}